Hybrid maize plant &amp; seed (3310)

ABSTRACT

According to the invention, there is provided a hybrid maize plant, designated as 3310, produced by crossing two Pioneer Hi-Bred International, Inc. proprietary inbred maize lines. This invention relates to the hybrid seed 3310, the hybrid plant produced from the seed, and variants, routants, and trivial modifications of hybrid 3310.

FIELD OF THE INVENTION

This invention is in the field of maize breeding, specifically relatingto a hybrid maize line designated 3310.

BACKGROUND OF THE INVENTION Plant Breeding

Field crops are bred through techniques that take advantage of theplant's method of pollination. A plant is self-pollinated if pollen fromone flower is transferred to the same or another flower of the sameplant. A plant is cross-pollinated if the pollen comes from a flower ona different plant.

Plants that have been self-pollinated and selected for type for manygenerations become homozygous at almost all gene loci and produce auniform population of true breeding progeny. A cross between twodifferent homozygous lines produces a uniform population of hybridplants that may be heterozygous for many gene loci. A cross of twoplants each heterozygous at a number of gene loci will produce apopulation of hybrid plants that differ genetically and will not beuniform.

Maize (Zea mays L.), often referred to as corn in the U.S., can be bredby both self-pollination and cross-pollination techniques. Maize hasseparate male and female flowers on the same plant, located on thetassel and the ear, respectively. Natural pollination occurs in maizewhen wind blows pollen from the tassels to the silks that protrude fromthe tops of the ears.

The development of a hybrid maize variety involves three steps: (1) theselection of plants from various germplasm pools for initial breedingcrosses; (2) the selfing of the selected plants from the breedingcrosses for several generations to produce a series of inbred lines,which, although different from each other, breed true and are highlyuniform; and (3) crossing the selected inbred lines with unrelatedinbred lines to produce the hybrid progeny (F₁). During the inbreedingprocess in maize, the vigor of the lines decreases. Vigor is restoredwhen two different inbred lines are crossed to produce the hybridprogeny (F₁). An important consequence of the homozygosity andhomogeneity of the inbred lines is that the hybrid created by crossing adefined pair of inbreds will always be the same. Once the inbreds thatcreate a superior hybrid have been identified, a continual supply of thehybrid seed can be produced using these inbred parents and the hybridcorn plants can then be generated from this hybrid seed supply.

Large scale commercial maize hybrid production, as it is practicedtoday, requires the use of some form of male sterility system whichcontrols or inactivates male fertility. A reliable method of controllingmale fertility in plants also offers the opportunity for improved plantbreeding. This is especially true for development of maize hybrids,which relies upon some sort of male sterility system. There are severaloptions for controlling male fertility available to breeders, such as:manual or mechanical emasculation (or detasseling), cytoplasmic malesterility, genetic male sterility, gametocides and the like.

Hybrid maize seed is typically produced by a male sterility systemincorporating manual or mechanical detasseling. Alternate strips of twoinbred varieties of maize are planted in a field, and the pollen-bearingtassels are removed from one of the inbreds (female). Providing thatthere is sufficient isolation from sources of foreign maize pollen, theears of the detasseled inbred will be fertilized only from the otherinbred (male), and the resulting seed is therefore hybrid and will formhybrid plants.

The laborious, and occasionally unreliable, detasseling process can beavoided by using cytoplasmic male-sterile (CMS) inbreds. Plants of a CMSinbred are male sterile as a result of factors resulting from thecytoplasmic, as opposed to the nuclear, genome. Thus, thischaracteristic is inherited exclusively through the female parent inmaize plants, since only the female provides cytoplasm to the fertilizedseed. CMS plants are fertilized with pollen from another inbred that isnot male-sterile. Pollen from the second inbred may or may notcontribute genes that make the hybrid plants male-fertile. Usually seedfrom detasseled fertile maize and CMS produced seed of the same hybridare blended to insure that adequate pollen loads are available forfertilization when the hybrid plants are grown.

There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. Theseand all patents referred to are incorporated by reference. In additionto these methods, Albertsen et al., of Pioneer Hi-Bred, U.S. patentapplication No. 07/848,433, have developed a system of nuclear malesterility which includes: identifying a gene which is critical to malefertility; silencing this native gene which is critical to malefertility; removing the native promoter from the essential malefertility gene and replacing it with an inducible promoter; insertingthis genetically engineered gene back into the plant; and thus creatinga plant that is male sterile because the inducible promoter is not "on"resulting in the male fertility gene not being transcribed. Fertility isrestored by inducing, or turning "on", the promoter, which in turnallows the gene that confers male fertility to be transcribed.

There are many other methods of conferring genetic male sterility in theart, each with its own benefits and drawbacks. These methods use avariety of approaches such as delivering into the plant a gene encodinga cytotoxic substance associated with a male tissue specific promoter oran antisense system in which a gene critical to fertility is identifiedand an antisense to that gene is inserted in the plant (see:Fabinjanski, et al. EPO 89/3010153.8 publication no. 329,308 and PCTapplication PCT/CA90/00037 published as WO 90/08828).

Another system useful in controlling male sterility makes use ofgametocides. Gametocides are not a genetic system, but rather a topicalapplication of chemicals. These chemicals affect cells that are criticalto male fertility. The application of these chemicals affects fertilityin the plants only for the growing season in which the gametocide isapplied (see Carlson, Glenn R., U.S. Pat. No. 4,936,904). Application ofthe gametocide, timing of the application and genotype specificity oftenlimit the usefulness of the approach.

The use of male sterile inbreds is but one factor in the production ofmaize hybrids. The development of maize hybrids requires, in general,the development of homozygous inbred lines, the crossing of these lines,and the evaluation of the crosses. Breeding programs combine the geneticbackgrounds from two or more inbred lines or various other broad-basedsources into breeding pools from which new inbred lines are developed byselfing and selection of desired phenotypes. The new inbreds are crossedwith other inbred lines and the hybrids from these crosses are evaluatedto determine which of those have commercial potential.

There are many important factors to be considered in the art of plantbreeding, such as the ability to recognize important morphological andphysiological characteristics, the ability to design evaluationtechniques for genotypic and phenotypic traits of interest, and theability to search out and exploit the genes for the desired traits innew or improved combinations.

The objective of commercial maize hybrid line development programs is todevelop new inbred lines to produce hybrids that combine to produce highgrain yields and superior agronomic performance. The primary traitbreeders seek is yield. However, many other major agronomic traits areof importance in hybrid combination and have an impact on yield orotherwise provide superior performance in hybrid combinations. Suchtraits include percent grain moisture at harvest, relative maturity,resistance to stalk breakage, resistance to root lodging, grain quality,and disease and insect resistance. In addition, the lines per se musthave acceptable performance for parental traits such as seed yields,kernel sizes, pollen production, all of which affect ability to provideparental lines in sufficient quantity and quality for hybridization.These traits have been shown to be under genetic control and many if notall of the traits are affected by multiple genes.

Pedigree Breeding

The pedigree method of breeding is the mostly widely used methodologyfor new hybrid line development.

In general terms this procedure consists of crossing two inbred lines toproduce the non-segregating F₁ generation, and self pollination of theF₁ generation to produce the F₂ generation that segregates for allfactors for which the inbred parents differ. An example of this processis set forth below. Variations of this generalized pedigree method areused, but all these variations produce a segregating generation whichcontains a range of variation for the traits of interest.

EXAMPLE 1 Hypothetical Example of Pedigree Breeding Program

Consider a cross between two inbred lines that differ for alleles atfive loci.

The parental genotypes are:

    ______________________________________                                         ##STR1##                                                                                  ##STR2##                                                         ______________________________________                                    

the F₁ from a cross between these two parents is:

    ______________________________________                                        F.sub.1       A b C d e F /a B c D E f                                        ______________________________________                                    

Selfing F₁ will produce an F₂ generation including the followinggenotypes:

    ______________________________________                                                  ##STR3##                                                        

    ______________________________________                                    

The number of genotypes in the F₂ is 3⁶ for six segregating loci (729)and will produce (2⁶)-2 possible new inbreds, (62 for six segregatingloci).

Each inbred parent which is used in breeding crosses represents a uniquecombination of genes, and the combined effects of the genes define theperformance of the inbred and its performance in hybrid combination.There is published evidence (Smith, O. S., J. S. C. Smith, S. L. Bowen,R. A. Tenborg and S. J. Wall, TAG 80:833-840 (1990)) that each of thelines are different and can be uniquely identified on the basis ofgenetically-controlled molecular markers.

It has been shown (Hallauer, Amel R. and Miranda, J. B. Fo. QuantitativeGenetics in Maize Breeding, Iowa State University Press, Ames Iowa,1981) that most traits of economic value in maize are under the geneticcontrol of multiple genetic loci, and that there are a large number ofunique combinations of these genes present in elite maize germplasm. Ifnot, genetic progress using elite inbred lines would no longer bepossible. Studies by Duvick and Russell (Duvick, D. N., Maydica37:69-79, (1992); Russell, W. A., Maydica XXIX:375-390 (1983)) haveshown that over the last 50 years the rate of genetic progress incommercial hybrids has been between one and two percent per year.

The number of genes affecting the trait of primary economic importancein maize, grain yield, has been estimated to be in the range of 10-1000.Inbred lines which are used as parents for breeding crosses differ inthe number and combination of these genes. These factors make the plantbreeders task more difficult. Compounding this is evidence that no oneline contains the favorable allele at all loci, and that differentalleles have different economic values depending on the geneticbackground and field environment in which the hybrid is grown. Fiftyyears of breeding experience suggests that there are many genesaffecting grain yield and each of these has a relatively small effect onthis trait. The effects are small compared to breeders' ability tomeasure grain yield differences in evaluation trials. Therefore, theparents of the breeding cross must differ at several of these loci sothat the genetic differences in the progeny will be large enough thatbreeders can develop a line that increases the economic worth of itshybrids over that of hybrids made with either parent.

If the number of loci segregating in a cross between two inbred lines isn, the number of unique genotypes in the F₂ generation is 3^(n) and thenumber of unique inbred lines from this cross is {(2^(n))-2}. Only avery limited number of these combinations are useful. Only about 1 in10,000 of the progeny from F₂ 's are commercially useful.

By way of example, if it is assumed that the number of segregating lociin F₂ is somewhere between 20 and 50, and that each parent is fixed forhalf the favorable alleles, it is then possible to calculate theapproximate probabilities of finding an inbred that has the favorableallele at {(n/2)+m} loci, where n/2 is the number of favorable allelesin each of the parents and m is the number of additional favorablealleles in the new inbred. See Example 2 below. The number m is assumedto be greater than three because each allele has so small an effect thatevaluation techniques are not sensitive enough to detect differences dueto three or less favorable alleles. The probabilities in Example 2 areon the order of 10⁻⁵ or smaller and they are the probabilities that atleast one genotype with (n/2)=m favorable alleles will exist.

To put this in perspective, the number of plants grown on 60 millionacres (approximate U.S. corn acreage) at 25,000 plants/acre is 1.5×10¹².

EXAMPLE 2 Probability of Finding an Inbred with m of n Favorable Alleles

Assume each parent has n/2 of the favorable alleles and only 1/2 of thecombinations of loci are economically useful.

    ______________________________________                                        No. of  No. of favorable                                                                          No. additional                                            segregating                                                                           alleles in Parents                                                                        favorable alleles in                                                                       Probability that                             loci (n)                                                                              (n/2)       new inbred   genotype occurs*                             ______________________________________                                        20      10          14           3 × 10.sup.-5                          24      12          16           2 × 10.sup.-5                          28      14          18           1 × 10.sup.-5                          32      16          20           8 × 10.sup.-6                          36      18          22           5 × 10.sup.-6                          40      20          24           3 × 10.sup.-6                          44      22          26           2 × 10.sup.-6                          48      24          28           1 × 10.sup.-6                          ______________________________________                                         *Probability that a useful combination exists, does not include the           probability of identifying this combination if it does exist.            

The possibility of having a usably high probability of being able toidentify this genotype based on replicated field testing would be mostlikely smaller than this, and is a function of how large a population ofgenotypes is tested and how testing resources are allocated in thetesting program.

Pioneer research station staff propose about 400 to 500 new inbreds eachyear from over 2,000,000 pollinations. Of those proposed new inbreds,less than 50, and more commonly less than 30, are actually selected forcommercial use.

SUMMARY OF THE INVENTION

According to the invention, there is provided a hybrid maize plant,designated as 3310, produced by crossing two Pioneer Hi-BredInternational, Inc. proprietary inbred maize lines. This invention thusrelates to the hybrid seed 3310, the hybrid plant produced from theseed, and variants, mutants and trivial modifications of hybrid 3310.This hybrid maize plant is high yielding and demonstrates very strongearly growth and very good staygreen. For an early maturing hybrid,Hybrid 3310 demonstrates good resistance to the Southeastern VirusComplex, a dual infection of both Maize Dwarf Mosaic Virus and MaizeChlorotic Dwarf Virus in a relatively early CRM. Hybrid 3310demonstrates good resistance to Gray Leaf Spot and demonstrates goodsilage appearance. This hybrid demonstrates very good test weight andvery good grain appearance. For its maturity, Hybrid 3310 yields well inhigh disease, no-till environments. It is best adapted for theNortheastern, Southeastern, Southcentral and Eastern regions of the U.S.It is also well suited to regions where MDM-MCDV is a problem.

DEFINITIONS

In the description and examples that follow, a number of terms are usedherein. In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided. NOTE: ABS is in absolute termsand % MN is percent of the mean for the experiments in which the inbredor hybrid was grown. These designators will follow the descriptors todenote how the values are to be interpreted. Below are the descriptorsused in the data tables included herein.

ANT ROT=ANTHRACNOSE STALK ROT (Colletotrichum graminicola). A 1 to 9visual rating indicating the resistance to Anthracnose Stalk Rot. Ahigher score indicates a higher resistance.

BAR PLT=BARREN PLANTS. The percent of plants per plot that were notbarren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near thetime of pollination, and is an indication of whether a hybrid or inbredwould snap or break near the time of flowering under severe winds. Dataare presented as percentage of plants that did not snap in pairedcomparisons and on a 1 to 9 scale (9=highest resistance) inCharacteristics Charts.

BU ACR=YIELD (BUSHELS/ACRE). Yield of the grain at harvest in bushelsper acre adjusted to 15.5% moisture.

CLN=CORN LETHAL NECROSIS (synergistic interaction of maize chloroticmottle virus (MCMV) in combination with either maize dwarf mosaic virus(MDMV-A or MDMV-B) or wheat streak mosaic virus (WSMV)). A 1 to 9 visualrating indicating the resistance to Corn Lethal Necrosis. A higher scoreindicates a higher resistance.

COM RST=COMMON RUST (Puccinia sorghi). A 1 to 9 visual rating indicatingthe resistance to Common Rust. A higher score indicates a higherresistance.

CRM=COMPARATIVE RELATIVE MATURITY (see PRM).

D/D=DRYDOWN. This represents the relative rate at which a hybrid willreach acceptable harvest moisture compared to other hybrids on a 1-9rating scale. A high score indicates a hybrid that dries relatively fastwhile a low score indicates a hybrid that dries slowly.

D/E=DROPPED EARS. Represented in a 1 to 9 scale in the CharacteristicsChart, where 9 is the rating representing the least, or no, droppedears.

DIP ERS=DIPLODIA EAR MOLD SCORES (Diplodia maydis and Diplodiamacrospora). A 1 to 9 visual rating indicating the resistance toDiplodia Ear Mold. A higher score indicates a higher resistance.

DRP EAR=DROPPED EARS. A measure of the number of dropped ears per plotand represents the percentage of plants that did not drop ears prior toharvest.

D/T=DROUGHT TOLERANCE. This represents a 1-9 rating for droughttolerance, and is based on data obtained under stress conditions. A highscore indicates good drought tolerance and a low score indicates poordrought tolerance.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to thehighest placed developed ear node attachment and is measured in inches.This is represented in a 1 to 9 scale in the Characteristics Chart,where 9 is highest.

EAR MLD=General Ear Mold. Visual rating (1-9 score) where a "1" is verysusceptible and a "9" is very resistant. This is based on overall ratingfor ear mold of mature ears without determining the specific moldorganism, and may not be predictive for a specific ear mold.

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher therating the larger the ear size.

ECB 1LF=EUROPEAN CORN BORER FIRST GENERATION LEAF FEEDING (Ostrinianubilalis). A 1 to 9 visual rating indicating the resistance topreflowering leaf feeding by first generation European Corn Borer. Ahigher score indicates a higher resistance.

ECB 2IT=EUROPEAN CORN BORER SECOND GENERATION INCHES OF TUNNELING(Ostrinia nubilalis). Average inches of tunneling per plant in thestalk.

ECB 2SC=EUROPEAN CORN BORER SECOND GENERATION (Ostrinia nubilalis). A 1to 9 visual rating indicating post flowering degree of stalk breakageand other evidence of feeding by European Corn Borer, Second Generation.A higher score indicates a higher resistance.

ECB DPE=EUROPEAN CORN BORER DROPPED EARS (Ostrinia nubilalis). Droppedears due to European Corn Borer. Percentage of plants that did not dropears under second generation corn borer infestation.

E/G=EARLY GROWTH. This represents a 1 to 9 rating for early growth,scored when two leaf collars are visible.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishmentin the spring and represents the number of plants that emerge on perplot basis for the inbred or hybrid.

EYE SPT=Eye Spot (Kabatiella zeae or Aureobasidium zeae). A 1 to 9visual rating indicating the resistance to Eye Spot. A higher scoreindicates a higher resistance.

FUS ERS=FUSARIUM EAR ROT SCORE (Fusarium moniliforme or Fusariumsubglutinans). A 1 to 9 visual rating indicating the resistance toFusarium ear rot. A higher score indicates a higher resistance.

G/A=GRAIN APPEARANCE. Appearance of grain in the grain tank (scored downfor mold, cracks, read streak, etc.).

GDU=Growing Degree Units. Using the Barger Heat Unit Theory, thatassumes that maize growth occurs in the temperature range 50° F.-86° F.and that temperatures outside this range slow down growth; the maximumdaily heat unit accumulation is 36 and the minimum daily heat unitaccumulation is 0. The seasonal accumulation of GDU is a major factor indetermining maturity zones.

GDU PHY=GDU TO PHYSIOLOGICAL MATURITY. The number of growing degreeunits required for an inbred or hybrid line to have approximately 50percent of plants, at physiological maturity from time of planting.Growing degree units are calculated by the Barger method.

GDU SHD=GDU TO SHED. The number of growing degree units (GDUs) or heatunits required for an inbred line or hybrid to have approximately 50percent of the plants shedding pollen and is measured from the time ofplanting. Growing degree units are calculated by the Barger Method,where the heat units for a 24-hour period are: ##EQU1##

The highest maximum temperature used is 86° F. and the lowest minimumtemperature used is 50° F. For each inbred or hybrid it takes a certainnumber of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for aninbred line or hybrid to have approximately 50 percent of the plantswith silk emergence from time of planting. Growing degree units arecalculated by the Barger Method as given in GDU SHD definition.

GIB ERS=GIBBERELLA EAR ROT (PINK MOLD) (Gibberella zeae). A 1 to 9visual rating indicating the resistance to Gibberella Ear Rot. A higherscore indicates a higher resistance.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis). A 1 to 9 visual ratingindicating the resistance to Gray Leaf Spot. A higher score indicates ahigher resistance.

GOS WLT=Goss' Wilt (Corynebacterium nebraskense). A 1 to 9 visual ratingindicating the resistance to Goss' Wilt. A higher score indicates ahigher resistance.

GRN APP=GRAIN APPEARANCE. This is a 1 to 9 rating for the generalappearance of the shelled grain as it is harvested based on such factorsas the color of harvested grain, any mold on the grain, and any crackedgrain. High scores indicate good grain quality.

H/POP=YIELD AT HIGH DENSITY. Yield ability at relatively high plantdensities on 1-9 relative rating system with a higher number indicatingthe hybrid responds well to high plant densities for yield relative toother hybrids. A 1, 5, and 9 would represent very poor, average, andvery good yield response, respectively, to increased plant density.

HC BLT=HELMINTHOSPORIUM CARBONUM LEAF BLIGHT (Helminthosporiumcorbonum). A 1 to 9 visual rating indicating the resistance toHelminthosporium infection. A higher score indicates a higherresistance.

HD SMT=HEAD SMUT (Sphacelotheca reilana). This score indicates thepercentage of plants not infected.

INC D/A=GROSS INCOME (DOLLARS PER ACRE). Relative income per acreassuming drying costs of two cents per point above 15.5 percent harvestmoisture and current market price per bushel.

INCOME/ACRE. Income advantage of hybrid to be patented over other hybridon per acre basis.

INC ADV=GROSS INCOME ADVANTAGE. GROSS INCOME advantage of variety #1over variety #2.

L/POP=YIELD AT LOW DENSITY. Yield ability at relatively low plantdensities on a 1-9 relative system with a higher number indicating thehybrid responds well to low plant densities for yield relative to otherhybrids. A 1, 5, and 9 would represent very poor, average, and very goodyield response, respectively, to low plant density.

MDM CPX=MAIZE DWARF MOSAIC COMPLEX (MDMV=Maize Dwarf Mosaic Virus andMCDV=Maize Chlorotic Dwarf Virus). A 1 to 9 visual rating indicating theresistance to Maize Dwarf Mosaic Complex. A higher score indicates ahigher resistance.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture ofthe grain at harvest.

MST ADV=MOISTURE ADVANTAGE. The moisture advantage of variety #1 overvariety #2 as calculated by: MOISTURE of variety #2--MOISTURE of variety#1=MOISTURE ADVANTAGE of variety #1.

NLF BLT=Northern Leaf Blight (Helminthosporium turcicum or Exserohilumturcicum). A 1 to 9 visual rating indicating the resistance to NorthernLeaf Blight. A higher score indicates a higher resistance.

PHY CRM=CRM at physiological maturity.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant fromthe ground to the tip of the tassel in inches. This is represented as a1 to 9 scale, 9 highest, in the Characteristics Chart.

POL SC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount ofpollen shed. The higher the score the more pollen shed.

POL WT=POLLEN WEIGHT. This is calculated by dry weight of tasselscollected as shedding commences minus dry weight from similar tasselsharvested after shedding is complete.

It should be understood that the inbred can, through routinemanipulation of cytoplasmic or other factors, be produced in amale-sterile form. Such embodiments are also contemplated within thescope of the present claims.

POP K/A=PLANT POPULATIONS. Measured as 1000s per acre.

POP ADV=PLANT POPULATION ADVANTAGE. The plant population advantage ofvariety #1 over variety #2 as calculated by PLANT POPULATION of variety#2--PLANT POPULATION of variety #1=PLANT POPULATION ADVANTAGE of variety#1.

PRM=PREDICTED Relative Maturity. This trait, predicted relativematurity, is based on the harvest moisture of the grain. The relativematurity rating is based on a known set of checks and utilizes standardlinear regression analyses and is referred to as the ComparativeRelative Maturity Rating System that is similar to the MinnesotaRelative Maturity Rating System.

PRM SHD=A relative measure of the growing degree units (GDU) required toreach 50% pollen shed. Relative values are predicted values from thelinear regression of observed GDU's on relative maturity of commercialchecks.

PRO=PROTEIN RATING. Rating on a 1 to 9 scale comparing relative amountof protein in the grain compared to hybrids of similar maturity. A "1"score difference represents a 0.4 point change in grain protein percent(e.g., 8.0% to 8.4%).

P/Y=PROTEIN/YIELD RATING. Indicates, on a 1 to 9 scale, the economicvalue of a hybrid for swine and poultry feeders. This takes into accountthe income due to yield, moisture and protein content.

ROOTS (%)=Percent of stalks NOT root lodged at harvest.

R/L=ROOT LODGING. A 1 to 9 rating indicating the level of root lodgingresistance. The higher score represents higher levels of resistance.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that donot root lodge; plants that lean from the vertical axis as anapproximately 30° angle or greater would be counted as root lodged.

RTL ADV=ROOT LODGING ADVANTAGE. The root lodging advantage of variety #1over variety #2.

S/L=STALK LODGING. A 1 to 9 rating indicating the level of stalk lodgingresistance. The higher scores represent higher levels of resistance.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount ofscatter grain (lack of pollination or kernel abortion) on the ear. Thehigher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amountof vegetative growth after emergence at the seedling stage(approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure ofthe hybrid's worth based on information for up to five traits. A maizebreeder may utilize his or her own set of traits for the selectionindex. One of the traits that is almost always included is yield. Theselection index data presented in the tables represent the mean valueaveraged across testing stations.

SLF BLT=SOUTHERN LEAF BLIGHT (Helminthosporium maydis or Bipolarismaydis). A 1 to 9 visual rating indicating the resistance to SouthernLeaf Blight. A higher score indicates a higher resistance.

SLK CRM=CRM at Silking.

SOU RST=SOUTHERN RUST (Puccinia polysora). A 1 to 9 visual ratingindicating the resistance to Southern Rust. A higher score indicates ahigher resistance.

STA GRN=STAY GREEN. Stay green is the measure of plant health near thetime of black layer formation (physiological maturity). A high scoreindicates better late-season plant health.

STAND (%)=Percent of stalks standing at harvest.

STD ADV=STALK STANDING ADVANTAGE. The advantage of variety #1 overvariety #2 for the trait STK CNT.

STK CNT=NUMBER OF PLANTS. This is the final stand or number of plantsper plot.

STK LDG=STALK LODGING. This is the percentage of plants that did notstalk lodge (stalk breakage) as measured by either natural lodging orpushing the stalks and determining the percentage of plants that breakbelow the ear.

STW WLT=Stewart's Wilt (Erwinia stewartli). A 1 to 9 visual ratingindicating the resistance to Stewart's Wilt. A higher score indicates ahigher resistance.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure thedegree of blasting (necrosis due to heat stress) of the tassel at thetime of flowering. A 1 would indicate a very high level of blasting attime of flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate therelative size of the tassel. The higher the rating the larger thetassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams)just prior to pollen shed.

TEX EAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate therelative hardness (smoothness of crown) of mature grain. A 1 would bevery soft (extreme dent) while a 9 would be very hard (flinty or verysmooth crown).

TIL LER=TILLERS. A count of the number of tillers per plot that couldpossibly shed pollen was taken. Data is given as a percentage oftillers: number of tillers per plot divided by number of plants perplot.

TST WT (CHARACTERISTICS CHART)=Test weight on a 1 to 9 rating scale witha 9 being the highest rating.

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grainin pounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain inpounds for a given volume (bushel) adjusted for 15.5 percent moisture.

TSW ADV=TEST WEIGHT ADVANTAGE. The test weight advantage of variety #1over variety #2.

WIN M %=PERCENT MOISTURE WINS.

WIN Y %=PERCENT YIELD WINS.

YLD=YIELD. It is the same as BU ACR ABS.

YLD ADV=YIELD ADVANTAGE. The yield advantage of variety #1 over variety#2 as calculated by: YIELD of variety #1--YIELD variety #2=yieldadvantage of variety #1.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relativerating for yield based on plot ear piles. The higher the rating thegreater visual yield appearance.

DETAILED DESCRIPTION OF THE INVENTION

Pioneer Brand Hybrid 3310 is a single cross, yellow endosperm, dentmaize hybrid which is high yielding and demonstrates very strong earlygrowth and very good staygreen. For a relatively early CRM hybrid,Hybrid 3310 demonstrates good resistance to the Southeastern VirusComplex, a dual infection of both Maize Dwarf Mosaic Virus and MaizeChlorotic Dwarf Virus. Hybrid 3310 demonstrates good resistance to GrayLeaf Spot and demonstrates good silage appearance. This hybriddemonstrates very good test weight and very good grain appearance.Hybrid 3310 combines several important characteristics that are neededfor areas of high risk for disease and no-till acreage. Hybrid 3310demonstrates strong early growth, excellent overall disease resistanceand high yield. Hybrid 3310 demonstrates the unique combination of goodMDM/MCDV resistance and high yield. Hybrid 3310 exhibits this high yieldand MDM/MCDV resistance in a maturity that is earlier than most otherhybrids resistant to MDM/MCDV. Hybrid 3310 is approximately 113 relativematurity based on the Comparative Relative Maturity Rating System forharvest moisture grain.

This hybrid has the following characteristics based on the datacollected primarily at Johnston, Iowa.

                                      TABLE 1                                     __________________________________________________________________________    VARIETY DESCRIPTION INFORMATION                                               VARIETY = 3310                                                                __________________________________________________________________________      TYPE: (describe intermediate types in Comments section):                    2     1 = Sweet 2 = Dent 3 = Flint 4 = Flour 5 = Pop 6 = Ornamental             MATURITY:                                                                   DAYS  HEAT UNITS                                                              65    1,407                                                                             From emergence to 50% of plants in silk                             66    1,420                                                                             From emergence to 50% of plants in pollen                           5       114                                                                             From 10% to 90% pollen shed                                         69    1,422                                                                             From 50% silk to harvest at 25% moisture                                                          Standard                                                                           Sample                                       PLANT:                      Deviation                                                                          Size                                       292.0 cm  Plant Height (to tassel tip)                                                                      16.97                                                                              2                                          130.0 cm  Ear Height (to base of top ear node)                                                              14.14                                                                              2                                          19.5  cm  Length of Top Ear Internode                                                                       1.84 10                                         1         Average Number of Tillers                                                                         0.00 2                                          1.0       Average Number of Ears per Stalk                                                                  0.00 2                                          1.0       Anthocyanin of Brace Roots: 1 = Absent 2 = Faint 3 = Moderate 4               = Dark                                                                                            Standard                                                                           Sample                                       LEAF:                       Deviation                                                                          Size                                         11.5                                                                              cm  Width of Ear Node Leaf                                                                            0.14 10                                           84.7                                                                              cm  Length of Ear Node Leaf                                                                           0.42 10                                           6.0 CM  Number of leaves above top ear                                                                    0.28 10                                           15.5    Degrees Leaf Angle (measure from 2nd leaf                                                         6.36 2                                                    above ear at anthesis to stalk above leaf)                            3       Leaf Color                                                                         Dark Green                                                                          (Munsell code)                                                                              5GY34                                      1.0       Leaf Sheath Pubescence (Rate on scale from 1 = none to 9 = like               peach fuzz)                                                         7.5       Marginal Waves (Rate on scale from 1 = none to 9 = many)            8.5       Longitudinal Creases (Rate on scale from 1 = none to 9 = many)                                    Standard                                                                           Sample                                       TASSEL:                     Deviation                                                                          Size                                       8.4       Number of Primary Lateral Branches                                                                0.28 10                                         45.0      Branch Angle from Central Spike                                                                   0.00 2                                          6.5       Pollen Shed (rate on scale from 0 = male sterile to 9 = heavy                 shed)                                                               7         Anther Yellow                                                                              (Munsell code)                                                                            2.5YR54                                    1         Glume Color                                                                          Light Green                                                                         (Munsell code)                                                                            5GY46                                      1.0       Bar Glumes (Glume Bands): 1 = Absent 2 = Present                    6a.                                                                             EAR (Unhusked Data):                                                        11    Silk Color (3 days after emergence)                                                               Pink   (Munsell code)                                                                       7.5YR66                               1     Fresh Husk Color (25 days after 50% silking)                                                      Light Green                                                                          (Munsell code)                                                                       5GY56                                 21    Dry Husk Color (65 days after 50% silking)                                                        Buff   (Munsell code)                                                                       2.5Y8.4                               1     Position of Ear at Dry Husk Stage: 1 = Upright 2 = Horizontal 3 =             Pendant                           Upright                               5.5   Husk Tightness (Rate of Scale from 1 = very loose to 9 = very                 tight)                                                                  2     Husk Extension (at harvest): 1 = Short (ears exposed) 2 = Medium              (<8 cm)                                                                       3 = Long (8-10 cm beyond ear tip) 4 = Very Long (>10                                                            Medium                                                              Standard                                                                           Sample                                     6b.                                                                             EAR (Husked Ear Data):      Deviation                                                                          Size                                       19.6  cm  Ear Length          0.5656                                                                             10                                         48.3  mm  Ear Diameter at mid-point                                                                         1.2727                                                                             10                                         217.  gm  Ear Weight          25.031                                                                             10                                         15.2      Number of Kernel Rows                                                                             1.1313                                                                             10                                         2         Kernel Rows: 1 = Indistinct 2 = Distinct                                                                    Distinct                              1         Row Alignment: 1 = Straight 2 = Slightly Curved 3                                                           Straight                              13.8  cm  Shank Length        1.4142                                                                             10                                                                                 Average                               2         Ear Taper: 1 = Slight 2 = Average 3 = Extreme                                                     Standard                                                                           Sample                                       KERNEL (Dried):             Deviation                                                                          Size                                       12.3  mm  Kernel Length       0.1414                                                                             10                                         8.9   mm  Kernel Width        0.1414                                                                             10                                         4     mm  Kernel Thickness    0    10                                         8.62      % Round Kernels (Shape Grade)                                                                     1.5163                                                                             2                                          1         Aleurone Color Pattern: 1 = Homozygous 2 = Segregating                                                      Homozygous                            7         Aluerone Color                                                                          Yellow  (Munsell code)                                                                            2.5Y814                               7         Hard Endosperm Color                                                                    Yellow  (Munsell code)                                                                            2.5Y8.16                              3         Endosperm Type:                                                                         Normal Starch                                                       1 = Sweet (Su1) 2 = Extra Sweet (sh2) 3 = Normal Starch                       4 = High Amylose Starch 5 = Waxy Starch 6 = High Protein                      7 = High Lysine 8 = SuperSweet (se) 9 = High Oil                              10 = Other.sub.--                                                     33  gm  Weight per 100 Kernels (unsized sample)                                                           1.4142                                                                             2                                                                        Standard                                                                           Sample                                       COB:                        Deviation                                                                          Size                                         25.4                                                                              mm  Cob Diameter at mid-point                                                                         2.8410                                                                             10                                         14        Cob Color                                                                              Red        (Munsell code)                                                                          10R310                                2         Cob Strength  1 = Weak 2 = Strong                                     DISEASE RESISTANCE (Rate from 1 (most susceptible) to 9 (most                 resistant); leave blank                                                       if not tested; leave Race or Strain Options blank if polygenic:             A.    Leaf Blights, Wilts, and Local Infection Diseases                                 Anthracnose Leaf Blight ( Colletotrichum graminicola)               6         Common Rust (Puccinia sorghi)                                                 Common Smut (Ustilago maydis)                                       6         Eyespot (Kabatiella zeae)                                           8         Goss's Wilt (Clavibacter michiganense spp. nebraskense)             6         Gray Leaf Spot (Cercospora zeae-maydis)                                       Helminthosporium Leaf Spot (Bipolaris zeicola)                      5         Northern Leaf Blight (Exserohilum turcicum)                         5         Southern Leaf Blight (Bipolaris maydis)                             6         Southern Rust (Puccinia polysora)                                   8         Stewart's Wilt (Erwinia stewartii)                                            Other (Specify) --                                                  B.    Systemic Diseases                                                       7         Corn Lethal Necrosis (MCMV and MDMV)                                9         Head Smut (Sphacelotheca reiliana)                                            Maize Chlorotic Dwarf Virus (MDV)                                             Maize Chlorotic Mottle Virus (MCMV)                                 5         Maize Dwarf Mosaic Virus (MDMV)                                               Sorghum Downy Mildew of Corn (Peronosclerospora sorghi)                       Other (Specify) --                                                  C.    Stalk Rots                                                              4         Anthracnose Stalk Rot (Colletotrichum graminicola)                            Diplodia Stalk Rot (Stenocarpella maydis)                                     Fusarium Stalk Rot (Fusarium moniliforme)                                     Gibberella Stalk Rot (Gibberella zeae)                                        Other (Specify) --                                                  D.    Ear and Kernel Rots                                                               Aspergillus Ear and Kernel Rot (Aspergillus flavus)                           Diplodia Ear Rot (Stenocarpella maydis)                             3         Fusarium Ear and Kernel Rot (Fusarium moniliforme)                  6         Gibberella Ear Rot (Gibberella zeae)                                          Other (Specify) --                                                  10.                                                                             INSECT RESISTANCE (Rate from 1 (most susceptible) to 9 (most                  resistant);                                                                             (leave blank if not tested)                                                 Banks grass Mite (Oligonychus pratensis)                                      Corn Worm (Helicoverpa zea)                                                    Leaf Feeding                                                                  Silk Feeding                                                                   mg larval wt.                                                               Ear Damage                                                                    Corn Leaf Aphid (Rhopalosiphum maidis)                                        Corn Sap Beetle (Carpophilus dimidiatus)                                      European Corn Borer (Ostrinia nubilalis)                            3          1st Generation (Typically Whorl Leaf Feeding)                      5          2nd Generation (Typically Leaf Sheath-Collar Feeding)                         Stalk Tunneling                                                            2.4 cm tunneled/plant                                                           Fall Armyworm (Spodoptera fruqiperda)                                          Leaf Feeding                                                                  Silk Feeding                                                                  mg larval wt.                                                                Maize Weevil (Sitophilus zeamaize)                                            Northern Rootworm (Diabrotica barberi)                                        Southern Rootworm (Diabrotica undecimpunctata)                                Southwestern Corn Borer (Diatreaea grandiosella)                               Leaf Feeding                                                                  Stalk Tunneling                                                               cm tunneled/plant                                                            Two-spotted Spider Mite (Tetranychus urticae)                                 Western Rootworm (Diabrotica virgifrea virgifera)                             Other (Specify) --                                                    AGRONOMIC TRAITS:                                                           8         Staygreen (at 65 days after anthesis) (Rate on a scale from 1 =               worst to                                                                      excellent)                                                          0.7       % Dropped Ears (at 65 days after anthesis)                                    % Pre-anthesis Brittle Snapping                                               % Pre-anthesis Root Lodging                                         13.4      Post-anthesis Root Lodging (at 65 days after anthesis)              10,550    Kg/ha Yield (at 12-13% grain moisture)                              __________________________________________________________________________

Research Comparisons for Pioneer Hybrid 3310

Comparisons of characteristics for Pioneer Brand Hybrid 3310 were madeagainst Pioneer Brand Hybrids 3223, 3245 and 3293.

Table 2A compares Pioneer Hybrid 3310 and Pioneer Hybrid 3223. Theresults show that while Hybrid 3223 is higher yielding than Hybrid 3310,both hybrids are above average yielding and Hybrid 3310 demonstratessignificantly lower harvest moisture and significantly better testweight than Hybrid 3223. Hybrid 3310 also demonstrates significantlybetter seedling vigor than Hybrid 3223. Hybrid 3310 demonstrates aboveaverage staygreen and significantly better resistance to Gray Leaf Spot,Southern Leaf Blight, Stewart's Wilt and Southern Rust than Hybrid 3223.In addition, Hybrid 3310 exhibits greater resistance to Goss's Wilt,Corn Lethal Necrosis and MDM Complex than Hybrid 3223.

Table 2B compares Pioneer Hybrid 3310 and Pioneer Hybrid 3245. Theresults show that both hybrids are above average yielding. Hybrid 3310demonstrates significantly better seedling vigor, and significantlybetter staygreen than Hybrid 3245. Hybrid 3310 demonstratessignificantly better resistance to Gray Leaf Spot, Common Rust, SouthernRust, Northern Leaf Blight, Corn Lethal Necrosis and Maize Dwarf MosaicComplex Hybrid 3245. Hybrid 3310 demonstrates very good resistance toGoss's Wilt, Anthracnose Stalk Rot, and Stewart's Wilt.

Table 2C compares Pioneer Hybrid 3310 and Pioneer Hybrid 3293. Theresults show that Hybrid 3310 is higher yielding and demonstratessignificantly higher test weight than Hybrid 3293. Hybrid 3310 alsodemonstrates above average staygreen and significantly better staygreenand significantly better resistance to Gray Leaf Spot than Hybrid 3293.Hybrid 3310 demonstrates better resistance o both Maize Dwarf MosaicComplex and Corn Lethal Necrosis than Hybrid 3293. Hybrid 3310 alsodemonstrates better resistance to Southern Rust than Hybrid 3293. Inaddition, 3310 exhibits very good resistance to Goss's Wilt, Stewart'sWilt and Common Rust.

                                      TABLE 2A                                    __________________________________________________________________________    VARIETY #1 = 3310                                                             VARIETY #2 = 3223                                                             __________________________________________________________________________                   PRM BU  BU      TST SDG EST GDU                                           PRM SHD ACR ACR MNST                                                                              WT  VGR CNT SHD                                           ABS ABS ABS % MN                                                                              % MN                                                                              ABS % MN                                                                              % MN                                                                              % MN                               __________________________________________________________________________    TOTAL SUM                                                                            1   114 114 164.4                                                                             101 100 58.6                                                                              113 100 101                                       2   115 118 171.0                                                                             105 107 56.5                                                                              93  103 106                                       LOCS                                                                              26  36  129 129 136 87  88  63  54                                        REPS                                                                              26  36  170 170 181 105 142 87  85                                        DIFF                                                                              2   4   6.6 3   6   2.1 20  3   5                                         PR > T                                                                            .000#                                                                             .000#                                                                             .005#                                                                             .026+                                                                             .000#                                                                             .000#                                                                             .000#                                                                             .060*                                                                             .000#                              __________________________________________________________________________               GDU STK PLT EAR RT  STA STK BRT GRN                                           SLK CNT HT  HT  LDG GRN LDG STK APP                                % MN   % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                       __________________________________________________________________________    TOTAL SUM                                                                            1   100 100 104 102 96  121 102 85  103                                       2   105 102 103 111 106 123 97  95  96                                        LOCS                                                                              47  173 81  81  58  72  85  10  23                                        REPS                                                                              74  262 124 124 97  96  96  12  23                                        DIFF                                                                              5   2   1   8   10  1   5   10  7                                         PR > T                                                                            .000#                                                                             .000#                                                                             .033+                                                                             .000#                                                                             .024+                                                                             .745                                                                              .063*                                                                             .265                                                                              .374                               __________________________________________________________________________               DRP GLF NLF SLF GOS STW ANT HD                                                EAR SPT BLT BLT WLT WLT ROT SMT CLN                                           % MN                                                                              ABS ABS ABS ABS ABS ABS ABS ABS                                __________________________________________________________________________    TOTAL SUM                                                                            1   98  5.6 5.3 5.5 8.0 8.0 3.8 100.0                                                                             7.5                                       2   102 3.2 5.5 3.5 7.3 7.0 3.1 100.0                                                                             3.0                                       LOCS                                                                              19  13  4   18  2   2   4   1   1                                         REPS                                                                              20  19  7   48  4   2   8   2   2                                         DIFF                                                                              5   2.3 0.3 2.0 0.8 1.0 0.6 0.0 4.5                                       PR > T                                                                            .259                                                                              .000#                                                                             .844                                                                              .000#                                                                             .500                                                                              .000#                                                                             .368                                       __________________________________________________________________________               MDM  FUS  EYE  COM  SOU ECB ECB ECB                                           CPX  ERS  SPT  RST  RST DPE 1LF 2SC                                           ABS  ABS  ABS  ABS  ABS ABS ABS ABS                                __________________________________________________________________________    TOTAL SUM                                                                            1   5.0  3.7  6.0  6.0  5.5 97.1                                                                              4.3 6.1                                       2   4.3  4.09 3.0  3.5  4.5 100.0                                                                             3.5 5.9                                       LOCS                                                                              3    5    1    2    2   2   2   8                                         REPS                                                                              8    7    1    3    4   2   4   9                                         DIFF                                                                              0.7  1.2  3.0  2.5  1.0 2.9 0.8 0.2                                       PR > T                                                                            .184 .255      1.26 .000#                                                                             .500                                                                              .500                                                                              .728                               __________________________________________________________________________     *= 10% SIG                                                                    += 5% SIG                                                                     #= 1% SIG                                                                

                                      TABLE 2B                                    __________________________________________________________________________    VARIETY #1 = 3310                                                             VARIETY #2 = 3245                                                             __________________________________________________________________________                   PRM BU  BU      TST SDG EST GDU                                           PRM SHD ACR ACR MNST                                                                              WT  VGR CNT SHD                                           ABS ABS ABS % MN                                                                              % MN                                                                              ABS % MN                                                                              % MN                                                                              % MN                               __________________________________________________________________________    TOTAL SUM                                                                            1   113 114 168.2                                                                             102 100 58.1                                                                              112 101 102                                       2   114 114 168.6                                                                             102 101 58.3                                                                              101 101 101                                       LOCS                                                                              39  42  184 184 194 118 99  97  56                                        REPS                                                                              39  42  239 239 252 141 133 125 64                                        DIFF                                                                              0   0   0.5 0   1   0.2 11  0   0                                         PR > T                                                                            .999                                                                              .999                                                                              .772                                                                              .999                                                                              .095*                                                                             .092*                                                                             .000#                                                                             .999                                                                              .999                               __________________________________________________________________________               GDU STK PLT EAR RT  STA STK BRT GRN                                           SLK CNT HT  HT  LDG GRN LDG STK APP                                % MN   % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                       __________________________________________________________________________    TOTAL SUM                                                                            1   102 101 104 103 97  124 100 87  106                                       2   103 101 100 96  103 103 99  103 104                                       LOCS                                                                              38  234 96  96  73  104 134 15  48                                        REPS                                                                              40  325 120 120 100 135 162 20  52                                        DIFF                                                                              1   0   4   7   6   21  1   16  1                                         PR > T                                                                            .002#                                                                             .999                                                                              .000#                                                                             .000#                                                                             .104                                                                              .000#                                                                             .435                                                                              .009#                                                                             .677                               __________________________________________________________________________               DRP GLF NLF SLF GOS STW ANT HD                                                EAR SPT BLT BLT WLT WLT ROT SMT CLN                                           % MN                                                                              ABS ABS ABS ABS ABS ABS ABS ABS                                __________________________________________________________________________    TOTAL SUM                                                                            1   99  5.4 4.8 4.8 8.0 8.0 4.6 99.3                                                                              7.3                                       2   101 4.2 2.7 4.5 8.0 4.5 2.9 94.4                                                                              4.8                                       LOCS                                                                              38  37  8   6   2   2   8   3   2                                         REPS                                                                              46  38  15  11  4   2   17  6   4                                         DIFF                                                                              2   1.2 2.1 0.3 0.0 3.5 1.7 4.9 2.5                                       PR > T                                                                            .185                                                                              .000#                                                                             .003#                                                                             .501                                                                              .999                                                                              .090*                                                                             .018+                                                                             .061*                                                                             .000#                              __________________________________________________________________________               MDM FUS GIB EYE COM SOU ECB ECB ECB                                           CPX ERS ERS SPT RST RST DPE 1LF 2SC                                           ABS ABS ABS ABS ABS ABS ABS ABS ABS                                __________________________________________________________________________    TOTAL SUM                                                                            1   5.0 3.7 5.6 6.0 6.0 5.5 98.1                                                                              3.4 5.7                                       2   2.9 5.7 6.0 6.0 4.0 2.5 98.0                                                                              3.5 4.8                                       LOCS                                                                              4   7   2   1   2   2   3   4   22                                        REPS                                                                              11  11  5   1   3   4   5   9   29                                        DIFF                                                                              2.1 2.0 0.4 0.0 2.0 3.0 0.1 0.1 0.9                                       PR > T                                                                            .004#                                                                             .021#                                                                             .728    .000#                                                                             .000#                                                                             .941                                                                              .391                                                                              .097*                              __________________________________________________________________________                                               ECB                                                                           2IT                                                                           ABS                                __________________________________________________________________________                                 TOTAL SUM                                                                            1      2.4                                                                    2      1.8                                                                    LOCS   1                                                                      REPS   3                                                                      DIFF   0.6                                                                    PR > T                                    __________________________________________________________________________     *= 10% SIG                                                                    += 5% SIG                                                                     #= 1% SIG                                                                

                                      TABLE 2C                                    __________________________________________________________________________    VARIETY #1 = 3310                                                             VARIETY #2 = 3293                                                             __________________________________________________________________________                   PRM BU  BU      TST SDG EST GDU                                           PRM SHD ACR ACR MNST                                                                              WT  VGR CNT SHD                                           ABS ABS ABS % MN                                                                              % MN                                                                              ABS % MN                                                                              % MN                                                                              % MN                               __________________________________________________________________________    TOTAL SUM                                                                            1   113 114 171.3                                                                             104 102 57.9                                                                              115 101 102                                       2   113 111 167.1                                                                             101 101 56.2                                                                              111 100 98                                        LOCS                                                                              18  20  95  95  98  76  45  44  29                                        REPS                                                                              18  20  110 110 116 89  59  56  31                                        DIFF                                                                              0   3   4.1 2   1   1.7 3   2   3                                         PR > T                                                                            .999                                                                              .000#                                                                             .035+                                                                             .047+                                                                             .280                                                                              .000#                                                                             .399                                                                              .228                                                                              .000#                              __________________________________________________________________________               GDU STK PLT EAR RT  STA STK BRT GRN                                           SLK CNT HT  HT  LDG GRN LDG STK APP                                % MN   % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                                                              % MN                                       __________________________________________________________________________    TOTAL SUM                                                                            1   102 101 105 104 91  133 98  74  101                                       2   98  100 99  101 88  101 101 88  104                                       LOCS                                                                              22  121 42  42  31  56  67  5   30                                        REPS                                                                              22  161 47  47  36  70  80  7   34                                        DIFF                                                                              4   1   6   3   3   32  3   14  4                                         PR > T                                                                            .000#                                                                             .348                                                                              .000#                                                                             .006#                                                                             .467                                                                              .000#                                                                             .110                                                                              .074*                                                                             .249                               __________________________________________________________________________               DRP GLF NLF SLF GOS STW ANT HD                                                EAR SPT BLT BLT WLT WLT ROT SMT CLN                                           % MN                                                                              ABS ABS ABS ABS ABS ABS ABS ABS                                __________________________________________________________________________    TOTAL SUM                                                                            1   99  5.5 4.6 5.0 8.0 8.0 4.6 99.3                                                                              7.3                                       2   98  3.7 5.4 5.5 8.3 6.5 4.8 100.0                                                                             3.8                                       LOCS                                                                              26  26  6   5   2   2   8   3   2                                         REPS                                                                              33  36  12  10  4   2   17  6   4                                         DIFF                                                                              0   1.8 0.8 0.5 0.3 1.5 0.1 0.7 3.5                                       PR > T                                                                            .999                                                                              .011+                                                                             .351                                                                              .500                                                                              .205                                                                              .869                                                                              .423                                                                              .090*                                  __________________________________________________________________________               MDM FUS GIB COM SOU ECB ECB ECB ECB                                           CPX ERS ERS RST RST DPE 1LF 2SC 2IT                                           ABS ABS ABS ABS ABS ABS ABS ABS ABS                                __________________________________________________________________________    TOTAL SUM                                                                            1   5.3 3.4 8.6 6.0 5.5 100.0                                                                             3.4 5.1 2.4                                       2   2.4 4.2 7.2 6.0 2.5 96.7                                                                              3.1 4.6 3.0                                       LOCS                                                                              2   6   2   1   2   1   4   2   1                                         REPS                                                                              7   9   5   2   4   3   9   5   3                                         DIFF                                                                              2.8 0.8 1.6 0.0 3.0 3.3 0.3 0.5 0.6                                       PR > T                                                                            .037+                                                                             .370                                                                              .382    .000#   .391                                                                              .500                                   __________________________________________________________________________     *= 10% SIG                                                                    += 5% SIG                                                                     #= 13% SIG                                                               

Strip Test Data for Hybrid 3310

Comparison data was collected from strip tests that were grown byfarmers. Each hybrid was grown in strips of 4, 6, 8, 12, etc. rows infields depending on the size of the planter used. The data was collectedfrom strip tests that had the hybrids in the same area and weighed. Themoisture percentage was determined and bushels per acre was adjusted to15.5 percent moisture. The number of comparisons represent the number oflocations or replications for the two hybrids that were grown in thesame field in close proximity and compared.

Comparison strip testing was done between Pioneer Brand hybrid 3310 andPioneer Brand Hybrids 3293, 3245 and 3223. The comparisons come from allthe hybrid's adapted growing areas in the U.S.

These results are presented in Table 3. Hybrid 3310 has a 9.0 bushel peracre yield advantage and a $22.96 per acre income advantage over Hybrid3293. Hybrid 3310 has a 1.9 pound per bushel test weight advantage and a0.5 percentage point moisture advantage over Hybrid 3293.

Hybrid 3310 has a 1.7 pound per bushel test weight advantage and a 0.9percentage point moisture advantage over Hybrid 3223.

Hybrid 3310 also has a weighted average 0.5 percentage point moistureadvantage over the other hybrids and a weighted average 1.2 pound perbushel test weight advantage over the other hybrids.

                                      TABLE 3                                     __________________________________________________________________________    1995 PERFORMANCE COMPARISON REPORT FOR CORN                                   1 YEAR SUMMARY OF ALL STANDARD TEST TYPES.                                                               Income/                                                                            Pop Stand                                                                             Roots                                                                             test                              PIONEER      3310                                                                              151.8                                                                              21.3 361.50                                                                             24.3                                                                              90  97  57.2                              PIONEER      3293                                                                              142.8                                                                              21.8 338.54                                                                             24.8                                                                              92  95  55.3                              Advantage        9.0  0.5  22.96                                                                              0.5 -2  2   1.9                               Number of Comparisons                                                                          71   71   71   40  28  23  59                                Percent Wins     74   73   76   47  39  30  89                                Probability of Difference                                                                      99   99   99   78  76  97  99                                PIONEER      3310                                                                              146.7                                                                              17.5 360.42                                                                             23.4                                                                              95  100 58.8                              PIONEER      3245                                                                              150.2                                                                              17.4 369.04                                                                             22.7                                                                              98  100 59.0                              Advantage        -3.5 -0.1 -8.62                                                                              0.7 -3  0   -0.2                              Number of Comparisons                                                                          119  119  119  77  74  45  100                               Percent Wins     41   45   41   63  16  6   30                                Probability of Difference                                                                      98   68   98   98  99  8   82                                PIONEER      3310                                                                              147.0                                                                              18.9 357.06                                                                             24.0                                                                              95  100 58.3                              PIONEER      3223                                                                              147.2                                                                              19.8 355.19                                                                             24.1                                                                              94  100 56.6                              Advantage        -0.2 0.9  1.87 -0.1                                                                              1   0   1.7                               Number of Comparisons                                                                          203  203  203  112 98  67  173                               Percent Wins     51   809  53   41  24  7   85                                Probability of Difference                                                                      12   99   53   41  16  21  99                                PIONEER      3310                                                                              147.8                                                                              18.9 358.88                                                                             24.0                                                                              94  99  58.3                              WEIGHTED AVG     147.3                                                                              19.4 356.38                                                                             23.8                                                                              95  99  57.1                              Advantage        0.5  0.5  2.50 0.2 -1  0   1.2                               Number of Comparisons                                                                          393  393  393  229 200 135 332                               Percent Wins     52   68   53   49  23  11  69                                Probability of Difference                                                                      47   99   80   86  89  85  99                                __________________________________________________________________________     NOTE: The probability values are useful in analyzing if there is a "real"     difference in the genetic potential of the products involved. High values     are desirable, with 95% considered significant for real differences.     

Comparison of Key Characteristics for Hybrid 3310

Characteristics of Pioneer Hybrid 3310 are compared to Pioneer Hybrids3293, 3245 and 3223 in Table 4. The values given for most of the traitsare on a 1-9 basis. In these cases 9 would be outstanding, while 1 wouldbe poor for the given characteristics. These values are based onperformance of a given hybrid relative to other Pioneer commercial,precommercial and competitive hybrids that are grown in research striptest trials. These performance based values are determined utilizingseveral factors such as research data, experience the trained cornresearchers had in the field, and the sales experience with the hybridsin strip tests in the field. These values reflect the hybrid's relativeperformance to other hybrids for the characteristics listed. Table 4shows Hybrid 3310 demonstrates very good early growth and staygreen whencompared to other hybrids. In addition, the results show Hybrid 3310demonstrates above average scores for a combination of characteristicsincluding yield, dry down, resistance to stalk lodging, staygreen,drought tolerance, early growth and protein/yield ratio.

                                      TABLE 4                                     __________________________________________________________________________    Hybrid Patent Comparisons-Characteristics                                     Pioneer Hybrid 3310 vs. Pioneer Hybrids 3293, 3245 and 3223                   __________________________________________________________________________            SILK                                                                             PHY                                                                              GDU                                                                              GDU   H/ L/                                                  VARIETY                                                                            CRM                                                                              CRM                                                                              CRM                                                                              SILK                                                                             PHY                                                                              YLD                                                                              POP                                                                              POP                                                                              D/D                                                                              S/L                                                                              R/L                                        __________________________________________________________________________    3310 113                                                                              114                                                                              114                                                                              1420                                                                             2770                                                                             8  8  7  6  6  4                                          3293 114                                                                              111                                                                              112                                                                              1390                                                                             2720                                                                             7  8  9  4  8  4                                          3245 115                                                                              115                                                                              114                                                                              1440                                                                             2770                                                                             8  7  8  6  5  4                                          3223 116                                                                              117                                                                              116                                                                              1460                                                                             2830                                                                             9  9  8  6  5  7                                          __________________________________________________________________________         STA   TST   PLT EAR    BRT                                               VARIETY                                                                            GRN                                                                              D/T                                                                              WT E/G                                                                              HT  HT  D/E                                                                              STK PRO                                                                              P/Y                                        __________________________________________________________________________    3310 8  7  7  8  7   7      2   5  8                                          3293 7  7  5  8  5   6   4  3   6  8                                          3245 5  5  8  5  6   4   5  6   6  9                                          3223 7  8  5  6  8   9   5  3   4  8                                          __________________________________________________________________________

INDUSTRIAL APPLICABILITY

This invention includes hybrid maize seed of 3310 and the hybrid maizeplant produced therefrom. The foregoing was set forth by way of exampleand is not intended to limit the scope of the invention.

As used herein, the term plant includes plant cells, plant protoplasts,plant cell tissue cultures from which maize plants can be regenerated,plant calli, plant clumps, and plant cells that are intact in plants, orparts of plants, such as embryos, pollen, ovules, flowers, kernels,ears, cobs, leaves, seeds, husks, stalks, roots, root tips, anthers,silk and the like.

Duncan, Williams, Zehr, and Widholm, Plante, (1985) 165:322-332 reflectsthat 97% of the plants cultured which produced callus were capable ofplant regeneration. Subsequent experiments with both inbreds and hybridsproduced 91% regenerable callus which produced plants. In a furtherstudy in 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988),7:262-265 reports several media additions which enhance regenerabilityof callus of two inbred lines. Other published reports also indicatedthat "nontraditional" tissues are capable of producing somaticembryogenesis and plant regeneration. K. P. Rao, et al., Maize GeneticsCooperation Newsletter, 60:64-65 (1986), refers to somatic embryogenesisfrom glume callus cultures and B. V. Conger, et al., Plant Cell Reports,6:345-347 (1987) indicates somatic embryogenesis from the tissuecultures of maize leaf segments. Thus, it is clear from the literaturethat the state of the art is such that these methods of obtaining plantsare, and were, "conventional" in the sense that they are routinely usedand have a very high rate of success.

Tissue culture of maize is described in European Patent Application,publication 160,390, incorporated herein by reference. Maize tissueculture procedures are also described in Green and Rhodes, "PlantRegeneration in Tissue Culture of Maize," Maize for Biological Research(Plant Molecular Biology Association, Charlottesville, Va. 1982, at367-372) and in Duncan, et al., "The Production of Callus Capable ofPlant Regeneration from Immature Embryos of Numerous Zea MaysGeneotypes," 165 Plante 322-332 (1985). Thus, another aspect of thisinvention is to provide cells which upon growth and differentiationproduce maize plants having the genotype of 3310.

Maize is used as human food, livestock feed, and as raw material inindustry. The food uses of maize, in addition to human consumption ofmaize kernels, include both products of dry- and wet-milling industries.

Maize, including both grain and non-grain portions of the plant, is alsoused extensively as livestock feed, primarily for beef cattle, dairycattle, hogs, and poultry.

Industrial uses of maize include production of ethanol, maize starch inthe wet-milling industry and maize flour in the dry-milling industry.The industrial applications of maize starch and flour are based onfunctional properties, such as viscosity, film formation, adhesiveproperties, and ability to suspend particles. The maize starch and flourhave application in the paper and textile industries. Other industrialuses include applications in adhesives, building materials, foundrybinders, laundry starches, explosives, oil-well muds, and other miningapplications.

Plant parts other than the grain of maize are also used in industry.Stalks and husks are made into paper and wallboard and cobs are used forfuel and to make charcoal.

The seed of the hybrid maize plant and various parts of the hybrid maizeplant can be utilized for human food, livestock feed, and as a rawmaterial in industry.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity andunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the invention, as limited only bythe scope of the appended claims.

DEPOSITS

Applicants have made a deposit of at least 2500 seeds of Hybrid MaizeLine 3310 with the American Type Culture Collection (ATCC), Rockville,Md. 20852 U.S.A., ATCC Deposit No. 209335. The seeds deposited with theATCC on Oct. 6, 1997 were taken from the deposit maintained by PioneerHi-Bred International, Inc., 700 Capital Square, 400 Locust Street, DesMoines, Iowa 50809-2340 since prior to the filing data of thisapplication. This deposit of the Hybrid Maize Line 3310 will bemaintained in the ATCC depositor, which is a public depository, for aperiod of 30 years, or 5 years after the most recent request, or for theenforceable life of the patent, whichever is longer, and will bereplaced if it becomes nonviable during that period. Additionally,Applicant has satisfied all the requirements of 37 C.F.R. §§1.801-1.809,including providing an indiction of the viability of the sample.Applicant imposes no restrictions on the availability of the depositedmaterial from the ATCC; however, Applicant has no autherity to waive anyrestrictions imposed by law on the transfer of biological material orits transportation in commerce. Applicant does not waive anyinfringement of its rights granted under this patent.

We claim:
 1. Hybrid maize seed designated 3310, representative seed ofsaid hybrid 3310 having been deposited under ATCC accession number209335.
 2. A maize plant, and its parts, produced by the seed ofclaim
 1. 3. Pollen of the plant of claim
 2. 4. An ovule of the plant ofclaim
 2. 5. A tissue culture of regenerable cells of a hybrid maizeplant 3310, representative seed of said hybrid maize plant 3310 havingbeen deposited under ATCC accession number 209335, wherein the tissueregenerates plants capable of expressing all the morphological andphysiological characteristics of said hybrid maize plant
 3310. 6. Atissue culture according to claim 5, the cells or protoplasts being of atissue selected from the group consisting of leaves, pollen, embryos,roots, root tips, anthers, silks, flowers, kernels, ears, cobs, husks,and stalks.
 7. A maize plant, or its parts, regenerated from the tissueculture of claim 5 and capable of expressing all the morphological andphysiological characteristics of hybrid maize plant 3310, representativeseed having been deposited under ATCC accession number 209335.